/*
 *  Copyright 2007-2008 by Matthias Buch-Kromann <mbk.isv@cbs.dk>.
 *  *
 *  This file is part of the Open-source Dependency Toolkit (OSDT),
 *  see http://code.google.com/p/open-source-dependency-toolkit.
 *  
 *  The OSDT is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as 
 *  published by the Free Software Foundation, either version 3 of 
 *  the License, or (at your option) any later version.
 * 
 *  The OSDT is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 * 
 *  You should have received a copy of the GNU Lesser General Public 
 *  License along with the OSDT in the files COPYING and COPYING.LESSER.
 *  If not, see http://www.gnu.org/licenses.
 */

package org.osdtsystem.functions;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.osdtsystem.graphs.GraphAccessor;
import org.osdtsystem.values.Edge;
import org.osdtsystem.values.NodeID;

/**
 * A function that returns the union of all in-nodes for edges in the
 * input edge list.
 * @author Matthias Buch-Kromann <mbk.isv@cbs.dk>
 */
public class FuncInNode extends AbstractFunction<NodeID> {
    List<Function<? extends Edge>> edgeFunctions;

    public FuncInNode(Function<? extends Edge>... edgeFunctions) {
        super(edgeFunctions);
        this.edgeFunctions = Arrays.asList(edgeFunctions);
    }

    @Override
    public List<NodeID> _functionValue(LocalFunction<?, ?> caller, FunctionContext context,
            GraphAccessor accessor) {
        List<NodeID> nodes = new ArrayList<NodeID>();
        for (Function<? extends Edge> edgeFunction : edgeFunctions) {
            List<? extends Edge> edges = edgeFunction.functionValue(caller, context, accessor);
            for (Edge edge : edges)
                nodes.add(accessor.inNode(caller, edge.asEdge()));
        }
        return nodes;
    }

    @Override
    void toStringBuilder(FunctionStringBuilder builder) {
        builder.addSubfunctions(edgeFunctions);
    }
}
